Error in band-structure plotting when spin-orbit coupling is included in QE

[beckerhome]

Dear VNL Users,

I'm using VNL to plot band structures from Quantum Espresso calculations of perovskite like compounds, and in principle it works well. However, when i include spin-orbit coupling (lspinorb + noncolin) in the same calculations, VNL gives an error message "IOError: No such file or Directory: ..../spin-polarization.dat". I understand that it searches the obviously non-existent file spin-polarization.dat, but i do not know how to produce it or if it is really necessary. Maybe i'm too clueless about spin-polarized calculations.....

I would be very glad about any guidance.

Best regards
Markus

[Jess Wellendorff]

Dear Markus,
we will look into this and get back to you. I hopefully have a QE lspinorb bandstructure calculation lying around somewhere...
Regards,
Jess

[Jess Wellendorff]

Markus: It seems to me that this happens only if you in VNL select the electron density object and try to plot it, not if just plotting the band structure. Is this also your experience ?

[beckerhome]

Hello Jess,

indeed. I just tried a scf and subsequent bands calculation with spin-orbit. VNL can plot the bands with the band structure analyzer, but is unable to project the charge density. I guess this has to do with spin-up spin-down differences in a spin-polarized file. But i'am simply not sure.

However, thanks a lot for the reply.

Best regards 

[Jess Wellendorff]

Right, this is a bug in the VNL QuantumESPRESSO plugin: With nspins=2 (ordinary spin-polarized calculations), some charge-density data is written to "spin-polarization.dat". But with "noncolin=.true." the data is written to 3 files: "magnetization.x.dat", "magnetization.y.dat", and "magnetization.z.dat". VNL currently does not look for these files, but looks for spin-polarization.dat, which does not exist with noncolinear spin.

I have submitted a bug report on this, but I cannot say exactly when it will be fixed.